English
For field k and extension K, IsAlgClosure k K holds if and only if IsAlgClosed K and Algebra.IsAlgebraic k K.
Русский
Для поля k и расширения K условие IsAlgClosure k K эквивалентно IsAlgClosed K и Algebra.IsAlgebraic k K.
LaTeX
$$$\forall (k : Type u) [\mathrm{Field}\;k] (K : Type v) [\mathrm{Field}\;K] [\mathrm{Algebra}\;k K], IsAlgClosure k K \iff (IsAlgClosed K \wedge Algebra.IsAlgebraic k K)$$$
Lean4
theorem isAlgClosure_iff (K : Type v) [Field K] [Algebra k K] :
IsAlgClosure k K ↔ IsAlgClosed K ∧ Algebra.IsAlgebraic k K :=
⟨fun h => ⟨h.1, h.2⟩, fun h => ⟨h.1, h.2⟩⟩